TEMPERATURE DEPENDENCE OF NORMAL EMISSION PHOTOELECTRON DIFFRACTION AND ANALOGIES WITH EXAFS
The temperature dependence of normal-emission photoelectron diffraction (NPD) of the prototype adsorbate-substrate system Se-Ni (001) was studied. Two interesting observations emerged. Thermal diffuse scattering yielded a decreasing peak-to-valley contrast ratio in NPD with increasing temperature characterized by an effective temperature {Theta}{sub eff} {approx} 135 K. Also, a new low-temperature form of p(2 x 2) selenium structure was observed, with d{sub {perpendicular}} estimated to be larger by {approx}(0.06-0.1) {angstrom} than the room-temperature form. The new form, which is probably undissociated H{sub 2}Se, is apparent through a systematic NPD peak shift reminiscent of extended x-ray-absorption fine structure (EXAFS) spectra. It is noted that NPD, though usually associated with low-energy-electron diffraction, in fact has strong similarities to EXAFS. This is particularly evident in the importance of an extended k-space data set and in the temperature sensitivity.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Materials Sciences Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 1000031
- Report Number(s):
- LBL-11199; TRN: US201024%%266
- Journal Information:
- Physical Review B, Vol. 23, Issue 2; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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